The present invention relates to semiconductor memory devices and, more particularly, to phase-change and resistance-change random access memory devices.
Phase-change Random Access Memory (PRAM) devices are a type of non-volatile memory that stores data using a material (hereinafter a “phase-change material”) that has a resistance that varies as the phase of the material changes in response to temperature variations. An example of such a phase-change material is Ge—Sb—Te (GST). PRAM devices include many of the advantages of Dynamic Random Access Memory (DRAM) devices and are also non-volatile memories that exhibit low-power consumption. Because of these advantageous characteristics, PRAM devices may be widely used in the future.